The invention relates to a terminal for the electrical connection of a flat conductor and, in particular, to a contact strip for a flat conductor of a flexible conductor film.
A terminal for flat conductor cable is disclosed by U.S. Pat. No. 4,082,402 issued Apr. 4, 1978 to Kinkaid et al. Flat electrical cables such as ribbon cable or flexible conductor film are generally known and have been in use for several years now, principally for connection purposes. The term "flexible conductor film" is generally used for a polyester film serving as a carrier, with a copper layer applied thereto, which is etched to form a combination of several parallel conducting strips or a printed circuit board. Over the etched copper it is also possible to apply one or more electrically insulating flexible protection layers, with the object of protecting the conducting strips against undesired contacting, damage, oxidation through the effects of damp etc.
The use of flexible conductor film as wiring for electrical circuits, particularly in automobile technology, is reaching ever-increasing proportions. Flexible conductor film permits, on the one hand, a saving of space and weight compared with other wiring techniques and, on the other, a considerable simplification of the generally complex wiring to electrical instruments, lighting and electronic components.
In practice, it is therefore necessary to be able to produce interconnection in a simple manner at any desired points on the film for the purpose of accommodating electrical components (resistors, capacitors, diodes etc.) on the flexible conductor film, but also in order to connect the conductors of one flexible conductor film in a simple manner to conductors of other flexible conductor film, signal wires, bridging wires etc.
For this purpose, various devices are known, but they are mainly designed for the connection of conductors of a flexible conductor film which is provided with a specific wiring pattern. Part of the insulation also generally has to be removed from the conductors to be contacted, which is a relatively labour-intensive, time-consuming and therefore quite expensive operation, which is also less suitable for the connection of the conductors by automatic means.
Another disadvantage is that the places where the insulation is removed are readily accessible to the effects of damp, which can cause oxidation and in the long run does not benefit the reliability of the connections. In automobile technology, such connections are therefore highly undesirable. The connection of the conductors by means of soldered connections also adversely affects the flexibility of the film.
The terminal of the aforenoted U.S. Pat. No. 4,082,402 has the advantage that in this case no insulation material need be removed from the conductor. The pointed projecting teeth of this terminal, which are situated opposite each other, can penetrate first on either side of the conductor through the insulation and then, if necessary, through the conductor, following which they are bent over backwards in such a way that mainly the pointed ends of these teeth produce an electrical connection with the conductor. Since the distance between opposite teeth is slightly smaller that the width of the conductor, the conductor will in general undergo a considerable deformation on its edges.
Because the teeth in this terminal lie along the edges of the contact strip on either side of the elongated conductor, this configuration is not suitable for use as a contact strip for connecting two conductors forming arbitrary angles with each other. For, a separate contact strip will always be needed for each angular position, in such a way that the teeth always lie on either side of the conductor.
Due to the fact that the conductor is enclosed between the teeth, the same terminal is also less suitable for contacting conductors of various widths. For, in the case of a narrower conductor and relatively long teeth, the pointed ends of the teeth can be bent past the edge of this conductor, as a result of which no contact is made with the conductor. In the case of broad conductors, it can, on the other hand, happen that the teeth are not strong enough to penetrate through the copper layer of the conductor film, which offers relatively more mechanical resistance.